This invention relates to automatic tape threading devices, and more particularly it is concerned with an automatic tape threading device for a magnetic recording and reproducing system for commercial use.
In a magnetic recording and reproducing system for the automatic tape threading device used has hitherto been mainly of the type in which a magnetic tape having connected thereto a leading tape member of larger width than the magnetic tape having suitable rigidity is wound in a cartridge beforehand, and when it is necessary to effect threading of the magnetic tape the leading tape member is withdrawn from the cartridge and moved in a predetermined path of travel including the outer periphery of a drum having a built-in rotary magnetic head until the leading tape member reaches a takeup reel when the takeup reel is actuated to wind the magnetic tape thereon, to complete threading of the magnetic tape. This type of automatic threading device is what is referred to as a leading tape member withdrawing system. Some disadvantages are associated with this system. For example, when the leading tape member having rigidity is forced into a guide groove, the leading tape member would tend to suffer buckling due to frictional dragging of the leading end of the leading tape member and its vicinity on the guide groove. This tendency is particularly strong when the radius of curvature of a bend in the path of movement in which the magnetic tape moves while being guided is small, making it impossible for the leading tape member to be introduced into the bend. Thus it has hitherto been usual practice to avoid the provision of bends of a small radius of curvature to the path of travel of the magnetic tape in design.
Another type of automatic tape threading device known in the art has generally been referred to as a leading tape member connection system in which a leading tape member of the same width as a magnetic tape is loaded in the predetermined path of travel of the tape while the magnetic tape has connected thereto a pin of a larger length than the tape width. The upper and lower end portions of the pin are interconnected by means of a J-shaped hook connected to one end of the leading tape member which is wound at the other end portion, to thereby carry out automatic tape threading. This connection system has, however, the disadvantage that there is the risk of the connection being disrupted when the magnetic tape is loosened longitudinally during the threading operation. In the event that the connection between the leading tape member and the magnetic tape is disrupted during the tape threading operation, it is impossible to automatically return the tape to the initial condition and try rethreading. To avoid this risk, a proposal has been made to provide means for preventing disruption of the connection in Japanese Patent Application Laid-Open No. 14310/75. The means for preventing the disruption of the connection disclosed therein is of the system in which a magnetic tape is connected to a leading tape member after a cartridge having the magnetic tape wound therein is loaded in the magnetic recording and reproducing system.